Currently, aircraft are limited in flight range and flight duration because of fuel capacity and fuel consumption. These limits require aircraft to return for refueling and also prevent them from unlimited flight ranges. Further, aircraft are also limited by weight constraints, such as the weight of the fuel necessary for travel that limits the speed and cargo capacity of the aircraft. Some airplanes use solar power to address these concerns, however, solar power systems experience power reductions due to weather and atmospheric changes, the Earth's annual and diurnal cycles, or solar eclipse. Therefore, aircraft that use solar power require supplemental or alternative sources of energy. Laser or microwave power beaming from the Earth's surface, from other aircraft, or from satellites orbiting the Earth can be used to supplement the solar power to aircraft.
Current systems that provide laser-beamed power to aircraft by using photovoltaic (PV) arrays and receivers have problems with obtaining uniformity of power transfer across the PV array. A PV array designed for solar powered applications includes PV cells arranged on a flat planar surface. In solar powered spacecraft or terrestrial solar power applications, the planar PV array experience generally uniform, steady irradiance across all the cells in the array. However, planar PC arrays do not experience a uniform irradiance across all the cells in the array when illuminated with laser-beamed power. The intensity of the laser varies across the width of the beam, with higher intensity at the center of the beam and generally weaker intensity away from the center. The irradiance received by a planar laser-power PV receiver is therefore non-uniform, with the strongest rays at the center of the PV array and weaker rays impinging upon the PV cells toward the edges of the PV array.
There are standard software tools for analyzing performance of known sunlit solar PV arrays, specifically, tools are available to analyze groups of series-connected strings of cells that receive uniform, constant illumination, except for a few areas of complete shadow when the array is partially shaded. These software tools are not sufficient for analyzing performance of PV arrays with complex interconnections receiving complex, time-varying illumination from a power beam. Thus, PV arrays designed from these static tools will be either over-designed, which incurs additional cost and weight, or under-designed, which may lead to failure under some operating conditions.
There is currently no tool that can analyze the performance of a PV array for producing power from a beam of light when the intensity profile of the beam is not uniform across the array, the position of the beam center on the array varies unpredictably with time, and the rotation of the beam cross section relative to the PV array varies unpredictably with time.
Therefore, a system and method is needed for designing PV cells subject to non-uniform irradiance in a laser-powdered PV array.
The foregoing examples and limitations associated therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon reading of the specifications and study of the drawings.